1. Technical Field
The present invention relates to an optical device and an image display device.
2. Related Art
A technology in which, in order to increase the resolution of an image to be projected more than the resolution of an optical modulation device of a liquid crystal panel or the like, an axis of an image light emitted from the optical modulation device is shifted, is known from the related art. In addition, an optical path control device described in JP-A-2011-158589 is known as a device which shifts an axis of an image light.
The optical path control device described in JP-A-2011-158589 includes a glass plate, a moving section that holds the glass plate, a support section that supports the moving section, and a pair of plate springs that couples the moving section to the support section. Posture of the glass plate is changed by swinging (rotating) a retention member by using the plate spring as a rotation axis, and thereby light (image light) which is incident on the glass plate is deflected, and the axis is shifted.
In addition, the optical path control device described in JP-A-2011-158589 includes a drive source for swinging the retention member. The drive source includes a permanent magnet, a coil provided on the retention member, a drive circuit that is electrically coupled to the coil, and a yoke configured by a U-shaped soft magnetic material having one end disposed on the coil side and having the other end disposed on the permanent magnet side.
However, in the optical device described in JP-A-2011-158589, the yoke configured by the soft magnetic material is not transparent, and thus when the optical path control device is assembled, the coil and the permanent magnet are hardly visible through the yoke. For this reason, when the moving section swings, it is difficult to provide the coil and the permanent magnet in a suitable position in which the coil and the permanent magnet do not come into contact with each other. As a result, when swinging, the coil comes into contact with the permanent magnet, and thereby stability of the swinging of the moving section may decrease.